Proteins responsible for the folding of poly(A) in a 27 residue repeating structure will be purified and characterized. The organization of coding and intervening regions of the nuclear precursor of beta-globin mRNA will be analyzed by nuclease digestion experiments analogous to those done on poly(A)-RNP. The folding of DNA in the dihydrofolate reductase gene region of metaphase chromosomes will be investigated by image processing techniques.